Storage-battery element



Patented Nov. 23,1926.

* UNITED STATES 1, 07,920 PATENT OFFICE.

JUNJ'IRO SATO, H IGHLAN D PARK, MICHIGAN;

STORAGE-BATTERY ELEMENT.

No Drawing. Application filed April 4,

' This invention relates to a storage battery and has for its object toprovidecompositionsfor the positive and negative plates which willadhere firmly to the supporting grids at a higher degree of acidity thanis feasible with compositions at present used,

whereb the strength of the electrolyte used while 0 arging may be lessthan that now customarily used. By the use of the compositions hereindescribed, the acidity may be more uniformly distributed throughout 1the cell and the damage caused by the strong pastes of variouscompositions which are treated with an electric current in what is knownas the forming charge to produce positive and negative plates. Thenegative electrodes are of sponge lead, and the positive electrodesconsist mainly of peroxide of lead (PbO The electrolyte is dilutesulfuric acid. The positive and ne ative electrodes are arrangedalternately within a cell, the plates usual y being set vertically, the.adjacent plates being of opposite polarity and separated from eachother by insulating oxide means commonly consisting of t n groov woodenor hard rubber separators. In preparing the negative plates, grids.having their spaces filled with litharge, (PbO) are connected ascathodes with lead sheets as anodes in a bath of dilute sulfuric acid,and current is passed through the cell. Hydroen set free on passage ofthecu'rrent reduces the litharge to spon metallic lead which is porousand which s ould be firmly adher-v ent to the supporting grid of lead. 4

The positive plates consist of similar grids in. which the pastesprimarily consist of red lead -(Pb,O,) with a smaller percentage oflitharge. These are connected as cathodes with plates of sheet lead "asanodes, and when.

' current is passed through the grou immersed in dilute sulfuric acid,the lead on the olsgiye plates is changed to lead per- In formirig thepastes it is desirable to use a substance WhlGl'lWlll. cause the wderedmaterial to harden or set and acid has this property, but if usedintoo1924. Serial No. 704,286.

great concentration difficulty is found in causing the paste to adhereto the grid. Substances are sometimes added to increase the porosity ofthe active material, such a substance being pulverized pumice' stone andfor the purpose of increasing'the conductivity of the resulting activematerial, pulverized carbon usually inthe form of lamp black may beadded to the paste used in negative plates. In addition to thesematerials which has hitherto been used, I have found that if a binder,as asbestos fiber, in suitable proportion is added to the activematerials it will act as a cement to bind them together and to retardtheir disintegration in use. Furthermore, when asbestos or thelike'forms a part of the composition the strength of the acid used tomix the paste may be increased without loss of adhesion so that thedried paste may be made of a higher acidity than has hitherto beenconsidered feasible. 1 7

As a further means of preventing loosening of the paste from the grid, Ihave found that a coating formed by dip ing the pasted plates in asuspension of. 'e asbestos in water, willact as a 'cementitious surfacelayer which will greatly prolong the durability of the plates. 1

The method which I consider best inthe preparation of plates is asfollows: Forthe positive plates sixty parts of red lead are mixed withforty parts of litharge, a sufficient quantity of sulfuric acid ofspecific gravity 1.100, being added to form a suitable paste whichv isthoroughl mixed. After pasting, the plates are a in the airvfortwenty-four hours. The dried plates are dipped into sulfuric acid ofspecific avity' 1.100 and then dried again twelve ours, ture of about100 lowed to dryready for the forming char e, a current of about 1amperes being use with the plates in an acid solution of specificgravity 1.100. The negative plates will be gfepared by making amixtureof ninety-eig t parts of litharge with 1.80 parts bmding material, asasbestos, and 0.20 part lamp black bein thoroughly mixed. To this drymixture su ficient sulfuric acid of specific gravity 1.100 is added toform a suitable paste. The paste. is then a plied to the grids 1n theusual manner. A or the plates are dried in the air for twenty-four hoursthey are dipped insulfuric' acid of specific gravity 1.100, again driedtwelve hours, heat being maintained at a temperature of about 100degrees F. The

' forming charge will be about 1 amperes in abath of sulfuric acid ofspecific gravity The positive and negative plates so formed will beassembled in a cell with the usual sep' rators of wood or hard rubber,and the ter als of the plates of like polarity will be cc nectedtogether in groups in the usual manner.

In the charging of a battery electrolyte is usually sulfuric acid ofspecific gravity 1.350 to 1.360 (corresponding to about 45% H 80 andwhen fully charged the electroferred composition herein set forth theelectrolyte may have a s cific avit of 1.300 and after chargin- 1 willbe fd und that the electrolyte wil remain at substantially the samespecific ravity.

It is believed t at the increased durability of a battery having platesprepared as set forth is due to the more even distribution of the acidthrough the cell than has been possible in the methods of preparationhere-- tofore used.

What I claim is v A storage battery comprising positive platesconsisting of metallic grids containing an acid mixture of lead peroxideand ashes tos, and negative plates consisting of metallic grids,containing an acid 'inixture' of spongy lead, asbestos, and carbon.

In testimony whereof I aflix my signature. v

I JUNJIRO SATO.

